You start at 10 atm and -40 Celsius you move 20 atm and 70 Celsius what kind of change has happened

Explanation:

It is a physical change .

If we start from 10 atm of pressure and - 40 celsius of temperature to 20 atm of pressure and 70 celsius of temperature , it is a change in which pressure increases and temperature also increases that means heat is added up to the gas . If we cool the gas we can retrieve its earlier pressure and temperature .

So it is  a physical change . In physical change , we can retrieve the old position by simple means.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"